Automatic trim tab means for marine craft

ABSTRACT

A pair of trim tabs are pivotally connected to the transom of a boat adjacent to the water line. The angle of each trim tabs is adjusted automatically by an adjustable spring loaded linkage. The spring loaded linkage may be manually adjusted for the proper trim at a desired speed.

United States Patent [191 Banner [451 Sept. 25, 1973 AUTOMATIC TRIM TAB MEANS FOR MARINE CRAFT [76] Inventor: Philip M. Banner, 28 Oxford Rd.,

Massapequa, NY. 11758 [22] Filed: Dec. 28, 1971 [21] Appl. No.: 205,928

Related US. Application Data [63] Continuation-impart of Ser. No. 16,476, March 14,

1970, Pat. NO. 3,628,484.

B63b l/22 Field of Search 1l4/66.5 P, 66.5 R, ll4/66.5 S, 145 R [52] US. Cl.

[56] References Cited UNITED STATES PATENTS 3,200,782 8/1965 Walden et al. ll4/66.5 P

3,326,164 6/1967 Kercheval ll4/66.5 P 3,370,561 2/l968 llon 3,565,030 2/1971 Curtis ll4/66.5 P

Primary ExaminerMilton Buchler Assistant ExaminerBarry L. Kelmachter Attorney-James P. Malone [5 7] ABSTRACT 4 Claims, 2 Drawing Figures FIGI IFIGZ' INVENTOR. PHILIP M. BANN ER AUTOMATIC TRIM TAB MEANS FOR MARINE CRAFT This application is a continuation in part to my prior US. Pat. application Ser. No. 16,476, filed Mar. 14, 1970, and now US. Pat. No. 3,628,484, dated Dec. 21, 1971.

That patent shows a manually adjusted trim tab. The present application is an improvement in that the adjustment linkage is spring loaded so that it will automatically vary according to the speed of the boat. The spring pressure may be manually adjusted for the optimum trim at the desired speed. Once this adjustment is made for a given boat it need not be adjusted any further.

Trim tabs are commonly used by boats and yachts for adjusting the trim or leveling desired. This device will automatically correct the leveling of the craft to produce maximum speed and efficiency by lowering the fuel consumption, reducing the load upon an engine that'normally would work harder and produce lower speed, plus a smoother ride. Pressures exerted upon the boat levelers will correct the listing of a boat and therefore hull stress is reduced.

This invention operates automatically without the aid of electrical components of any hydraulic means that are both greatly affected by maintenance factors on or around the water. Such prior art devices are expensive, difficult and costly to repair that may also endanger the safety of a craft in the case of malfunction of one unit or another, under certain conditions.

The present invention provides an automatic system which is easily adjusted by turning a single component that will remain set in this position. Once the operator of a craft determines the greatest point of efficiency he sets and locks the unit accordingly. The difference in design and weight of boats establish a definite need for an adjustable unit that only needs to be set once. This system has a minimum of parts and a minimum potential for malfunction. It reduces the number of controls that an operator of a craft would normally have, leaving him free for other important navigation. This invention when adjusted properly and locked in position is easily resetable and will compensate for the differences in displacement of craft.

The suggested maximum angle of operation in degrees would be pre-set for the user at although provisions could be made to provide more movemement to a final position. As the craft increases its speed so will the pressure increase upon the boat levelers which one each controlled by a spring pressure self adjusting assembly. The greater the outside water pressure the more the tab will rise against the spring pressure. The addition of trim tabs to a boat changes its balancing position. At the greatest point of pressure against the trim tabs the spring assembly will contain pressure of the tab and keep it in this position until the speed is reduced and the angle of the tab descends. As the trim tab descends, the bow will rise again accordingly to the speed and the pressure produced on the tab.

Accordingly, a principal object of the invention is to provide new and improved trim tab means for marine craft.

Another object of the invention is to provide new and improved automatic trim tab means for marine craft comprising, a tab member pivotally mounted on the transom of a marine craft adjacent to the water level, a rigid elongated member, the lower end of said rigid member being pivotally connected to said tab member to rotate said member, ameans to automatically contr'ol the movement of said rigid member, comprising an interacting lever arm pivotally connected to the upper end of said rigid member and means to spring load said lever, whereby said interacting lever ann transfers the angular pressure exerted by the trim tab to vertical linear pressure on the spring load having the same pivot mounted surface as the hinge member on the trim tab and the same degree of angular movement.

Another object of the invention is to provide new and improved trim tab means for marine craft having a minimum of parts and eliminating all motorized or hydraulic power control and providing an automatically adjusting unit.

These and other objects of the invention will be apparent from the following specifications and drawings of which:

FIG. 1 is a sectional view of an embodiment of the invention.

FIG. 2 is a side view of FIG. 1.

The trim tab 1 is pivotally mounted to the transom 2, of the boat, and a rigid member 3, is pivotally connected to the upper side of the trim tab 1. A lever 4, is pivotally mounted to the transom at its forward end and pivotally connected to the upper end of the member 3 at its rear end. A hollow member 5, is fixedly mounted on the transom and contains a spring 6, which bears down upon the lever 4. The upper end of the spring 6 is adapted to be compressed by the lower end of the bolt member 7. The internal wall of the hollow member 5 is internally threaded and the bolt is screwed into these threads. By turning the bolt 7, the spring pressure on the lever 4, can be adjusted. The bolt 7 has an upper extension which is preferably square so that a handle or wrench 8 can be connected to it for the purposes of connecting the bolt to it. A locking nut 10 fits on the upper endof boat member 7 to lock the adjustment.

This device not only changes trim proportionally to speed but spring 6 also acts as a shock absorber which protects the tab or leveller from damage, for instance, if hit by a floating object.

The operation is as follows:

When the craft is standing still (not under way), the angle of the trim tab or tabs will be at maximum downward position of, for instance, 10 from the bottom line of the boat. 0 measurement occurs at a horizontal position of the levelers when same is exactly even with the line of the crafts bottom.

Movement of the craft at low speeds will place increased amounts of pressure against the trim tab according to the speed factor. As the speed increases, the pressure on the tab will become great, forcing more pressure upon the interacting lever arm and therefore the spring assembly inside the control unit. The spring is then pressurized within the housing and the adjustment bolt within. The compression increases with speed, the stress is transferred from the trim tabs so that they are adjusted automatically to the horizontal plane at maximum speed.

At maximum speed the trim tab is in the horizontal position and the control spring assembly depressed to the adjusted maximum position. At maximum speed or even at relatively high speeds under maximum the upward movement of the trim tabs causes the bow of the craft into a planing position where the boat travels at higher speeds, uses less fuel and less engine resolutions per minute to attain maximum movement over the bottom or miles per hour.

The high speed control adjustment compensates for different displacements of various designed craft, each of which perform differently at high speeds due to weight and design factors. This adjustment is locked by a spring assembly that must be forced down upon the adjusting bolt before being able to unlock the bolt and turn same. This adjustment should be made only once, it will accomplish the efficiency needed at slow, intermediate and high speeds.

The adjustment of the control unit can be accomplished by a turn handle operated from within the boat at the storm, having a socket attached thereto. Forcing downward pressure against the adjusting bolt will release the spring, allowing the bolt to turn.

This unit is highly versatile, it can be installed outside or inside the craft, the mounting straps are reversible to either side of the assembly, allowing two position installations. The inside installation would require a hole in the transom for the actuating lever above the water line, and the lever would have to be longer. All of the provisions of this invention to operate trim tabs automatically by changing the position of the bow of a vessel responsive to speed factors, weight and design factors is accomplished by permanently setting the spring pressure against the interacting lever arm assembly. At the same time, the spring-loading action of the spring and interacting lever arm assembly perform another important function, the stabilizing of said vessel automatically in its rolling motion sideways. The stress of said rolling motion caused by the seas or wind is compensated by the individual control of each side of said vessel having one automatic trim tab on each side of the transom, counteracting the rolling motion. The extra pressure exerted by the trim tab in a roll motion places additional stress upon the interacting lever assembly and the pre-set pressure spring forcing the vessel to correct the roll by the stabilizing effect of the trim tabs automatically spring operated.

I claim: 1. Automatic trim tab means for marine craft consisting of,

a tab member pivotally mounted on the transom of a marine craft adjacent to the water level,

a rigid elongated member the lower end of said member being pivotally connected to said tab member to rotate said'tab member,

a means to automatically control the movement of said rigid member, consisting of,

an interacting lever arm pivotally connected to the upper end of said rigid member and means to spring load said lever, whereby said interacting lever arm transfers the angular pressure exerted by the trim tab to vertical linear pressure on the spring load having the same pivot mounted surface as the hinge member on the trim tab and the same degree of angular movement.

2. Apparatus as in claim 1 wherein said means to spring load said lever comprise a hollow member fixedly mounted on said transom,

a spring mounted in said hollow member, said spring being adapted to bear on said lever and means to adjust the said spring.

3. Apparatus as in claim 2 wherein said spring adjusting means comprises,

an internally threaded portion of said hollow member,

anexternally threaded bolt mounted in said internally threaded hollow member,

said bolt being adapted to bear down on the upper end of said spring so that by turning said bolt the spring pressure can be adjusted,

said bolt extending upwardly from said hollow member so that it may be manually turned to adjust the spring pressure.

4. Apparatus as in claim 3 having means accessible above said hollow member to lock the adjustment of said bolt. 

1. Automatic trim tab means for marine craft consisting of, a tab member pivotally mounted on the transom of a marine craft adjacent to the water level, a rigid elongated member the lower end of said member being pivotally connected to said tab member to rotate said tab member, a means to automatically control the movement of said rigid member, consisting of, an interacting lever arm pivotally connected to the upper end of said rigid member and means to spring load said lever, whereby said interacting lever arm transfers the angular pressure exerted by the trim tab to vertical linear pressure on the spring load having the same pivot mounted surface as the hinge member on the trim tab and the same degree of angular movement.
 2. Apparatus as in claim 1 wherein said means to spring load said lever comprise a hollow member fixedly mounted on said transom, a spring mounted in said hollow member, said spring being adapted to bear on said lever and means to adjust the said spring.
 3. Apparatus as in claim 2 wherein said spring adjusting means comprises, an internally threaded portion of said hollow member, an externally threaded bolt mounted in said internally threaded hollow member, said bolt being adapted to bear down on the upper end of said spring so that by turning said bolt the spring pressure can be adjusted, said bolt extending upwardly from said hollow member so that it may be manually turned to adjust the spring pressure.
 4. Apparatus as in claim 3 having means accessible above said hollow member to lock the adjustment of said bolt. 